High-velocity laser-driven flyer impact on paraffin gel

Abstract

The penetrating ballistic impact of thin 100 micrometers aluminum projectiles, accelerated at high velocities by laser-induced shock wave, on parafin gel is investigated. The laser-driven flyer experiments were conducted at BELENOS laser facility and allow the acceleration of projectile at high velocity ranging from 170 m s${}^{-1}$ to 710 m s${}^{-1}$. The projectile is monitored during impact and penetration into gel targets using shadowgraphy with ultra-high speed camera. Its velocity is recorded by fast-imaging technics and correlated to Photonic Doppler Velocimeter (PDV) measurements. The ballistic impact phenomena such as the splash ejection on the front face of the gel target and the cavitation effect are analyzed. The strength resistance parameter in the Poncelet model of the gel is obtained from experimental data fit, which predicts the speed of a given fragment from its penetration depth in the target. The cavity dynamics highlights the influence of the strain rate on the mechanical behavior of paraffin gel target under penetrating ballistic impact.